Doctors, nurse practitioners and physician assistants at community clinics work long hours, treating multitudes of patients who often have more than one chronic illness.

Every day after work, Sandeep Lehil changes out of her lab coat and blue scrubs and sits cross-legged on a large, black pillow in her airy, quiet Los Feliz apartment. She takes two deep breaths and tries not to think about the patients she so desperately wants to help.

She pushes out thoughts of the man with heart problems who left her exam room in an ambulance. And the patient who walked out when she told him his tests indicated he could have HIV. And the woman who Lehil fears is addicted to pain pills.

"Meditation is the only thing that keeps me sane," said Lehil, a nurse practitioner in South Los Angeles. "It's like clearing your head of the anxieties and troubles you've had that day."

Lehil, 28, and others like her at community clinics throughout the U.S. are key players in the push to lower the nation's healthcare spending. They conduct physicals, refill medications and manage chronic diseases for low-income patients, providing the care necessary to keep them from requiring more costly medical treatment.

The jobs are demanding — providers spend long hours treating patients who have multiple chronic illnesses and often have gone years without care. Administrators have trouble finding enough doctors, nurse practitioners and physician assistants to staff their clinics.

That is expected to cause a major roadblock next year, when the bulk of the national healthcare reform law takes effect, aiming to help 30 million uninsured Americans gain coverage. In preparation, clinics — expected to get an influx of new patients — are stepping up recruitment and trying to hold on to the care providers they have. But burnout is common, and staff members often leave for less-stressful, higher-paying positions elsewhere.

"The workforce shortage is certainly one of the top challenges we are facing currently, and the expansion hasn't even occurred yet," said Carmela Castellano-Garcia, president of the California Primary Care Assn., which represents community clinics.

Lehil graduated in May from Johns Hopkins University with a master's degree in nursing and an idealistic goal: to make a difference in a medically underserved community. In July she started as a nurse practitioner at T.H.E. Clinic, a community health center in South Los Angeles.

Lehil said the work is fulfilling but draining, and busier than she ever could have anticipated. By the end of the week, she said, "it's almost like running on empty."

T.H.E. Clinic has eight full-time providers but needs 11. There are ongoing advertisements, and the clinic is "constantly fighting" for family practice providers, often competing with nearby centers, said human resources director Lilia Marin-Alvarez. To find new clinicians, T.H.E. Clinic and others rely heavily on the National Health Service Corps, which offers scholarships and loan repayment for those willing to work in underserved areas.

While still in school, Lehil saw an ad for T.H.E. Clinic. The name — To Help Everyone — immediately appealed to her. Lehil interviewed and, soon after, accepted a job offer. Now, Marin-Alvarez said she just has to make sure Lehil stays.

Lehil speaks quickly and walks with purpose. She wears Crocs, red-rimmed glasses and a loose ponytail, and she has several tattoos, including the infinity sign on her wrist and a flock of birds on her back. A stethoscope rests on her neck and two silver bangles on her wrist.

Raised in a tight-knit, professional Indian family in San Jose, Lehil attended UC Berkeley as an undergraduate and majored in public health. Her parents wanted her to be a doctor, but she decided to become a nurse practitioner, in part because medical school would have taken too long.

When Lehil started working at T.H.E. Clinic, she wondered how she could possibly see two dozen or more patients in a day. "It's not like they have one thing wrong with them," she said.

She took the time she needed, but it resulted in longer waits. When her patients became frustrated, Lehil just apologized and smiled.

During the first few weeks, she left each Friday with a dull headache, which she tried to shake off before Monday morning. To better manage the stress, Lehil started meditating an hour a day, at home and at the Zen Center of Los Angeles. She also moved to Los Feliz so she could take walks in Griffith Park in her free time.

On a Tuesday in the fall, Lehil arrives at work before 8 a.m. so she can get a head start on reviewing lab results and medications for the patients she expects to see that day. Hand sanitizer, a bottle of water and a clipboard filled with papers sit on her desk. She picks up a thermos and takes a sip. She wants to switch to green tea, but not today. She has 15 patients scheduled for this morning and 12 others this afternoon. "Today's a black tea day," she said.

For 10 hours, she moves quickly from one patient to the next, starting every visit the same way: "Hi, I'm Sandeep. I'm here to help you."